Told through a series of epistolary vignettes, the second novel in Melina Druga's World War I trilogy traces the lives of the Steward and Bartlette families as they contend with their children's and siblings' wartime absences. Newlyweds Hettie Steward and Geoffrey Bartlette wasted no time heading to the Western Front after the war began. In the wake of the couple's traumatic and untimely separation, their families begin to knit themselves together ever tighter. Matriarchs Lucretia Steward and Amelia Bartlette attempt to keep the home fires burning, unable to escape the tumult of the war. Hettie's brother and brother-in-law join her on the front lines. Back in Ontario, some households grow. Others remain painfully stagnant. Romantic relationships wax and wane as these bright-eyed young adults fall in and out of love with one another and wrestle with the tension between timeworn traditions and the shiny appeal of progress. Those Left Behind offers readers the opportunity to connect deeply with the characters they met in The Unmarriable Kind and Angel of Mercy. As five years of deaths, births, tragedies, and triumphs unfold, one question never strays far from center: How does one maintain strong filial bonds - and repair weakened ones - when the world is changing rapidly on all sides?